Each of the five projects in this Program Project application depends heavily on morphological procedures. It is prohibitively expensive to duplicate the equipment required in morphology, plus a single experienced technician is likely to be more cost effective than several part-time individuals. Furthermore, quality control will be enhanced if a core is established. These are the principal reasons that a morphology core is being requested. In addition to access to core equipment, the project directors will rely on core personnel for routine preparation of tissue for electron microscopy, cryostat sectioning, including immunocytochemical procedures, and routine printing of negatives. The core director will be responsible for all the operations of the core, and in particular, he will make certain that the work emanating from the core is of the highest possible quality.